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  <a href="http://www.sudokuwiki.org/Unit_Forcing_Chains">Dynamic Region Forcing Chains</a>
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   We can prove that the following assertions are all true:
   <ul>
    {0}
   </ul>
   One of the assumptions has to be true because <b>digit {1}</b> can go only into one of the <b>cells {5}</b> in <b>{2}</b>.<br/>
   As the conclusion is the same in all cases it follows that the conclusion must be true: <b>{3}</b>.<br/>
   Each assertion is proven by a dynamic forcing chain, each potentially consisting of multiple sub-chains.<br/>
   This solving technique is also called Unit Forcing Chains.
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  {4}
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